Reddit (NYSE: RDDT) jumps 12.6% as S&P 500 buying meets traffic risk

Reddit, Inc. (NYSE: RDDT) has returned to the centre of retail-investor attention after its shares surged 12.6% on August 14 following confirmation that the social platform will join the S&P 500. RDDT closed Friday at US$178.09, giving Reddit a market capitalisation of roughly US$34.3 billion, with the index change taking effect before trading begins on August 18. The immediate catalyst could create significant mechanical demand from funds that track the S&P 500, but index inclusion does not change Reddit’s underlying revenue, user growth or profitability. The more important question is whether a business already growing revenue above 60% can sustain that pace while volatile search referrals continue to constrain United States user growth.

Why did Reddit shares jump 12.6% on August 14?

S&P Dow Jones Indices confirmed that Reddit will replace AvalonBay Communities in the S&P 500 before the market opens on August 18. AvalonBay is being acquired by Equity Residential, with the combined property company expected to remain in the benchmark under the Vivmark Residential name.

The announcement immediately created expectations of additional demand for RDDT shares from index funds and exchange-traded funds that replicate the S&P 500.

J.P. Morgan analysts estimated that index-tracking funds could need to acquire about 16.7 million Reddit shares. That estimate is equivalent to approximately 2.8 times Reddit’s average daily trading volume since its 2024 IPO, based on the trading-volume data cited alongside the estimate.

Friday itself demonstrated the scale of the interest. Approximately 21.5 million Reddit shares traded, around four times the more recent 5.33 million average daily volume. The estimated 16.7 million shares of potential index demand would equal almost 78% of Friday’s entire trading volume, although actual index-related purchases can be distributed differently and should not be treated as a guaranteed single-session buying order.

RDDT finished at US$178.09 compared with US$158.12 on August 13. The stock is now approximately 10.1% above its August 7 close of US$161.70.

The longer comparison is less bullish. Reddit closed at US$203.27 on July 14, leaving the stock approximately 12.4% lower over one month even after Friday’s rally. Its 52-week range extends from US$119.27 to US$282.95, meaning RDDT remains roughly 37% below its annual high.

The index catalyst has therefore repaired part of the recent share-price damage without returning Reddit to the valuation levels reached during its strongest period.

Does joining the S&P 500 actually make Reddit more valuable?

S&P 500 inclusion is important, but primarily because of market structure rather than an immediate change in the economics of Reddit’s business.

Funds designed to replicate the index need exposure to its constituents. When a new company enters, those portfolios generally have to acquire shares, creating demand that would not otherwise have existed on that timetable.

Inclusion also broadens institutional ownership and places Reddit inside one of the world’s most closely followed equity benchmarks.

None of that automatically increases advertising revenue, daily users or free cash flow.

That distinction becomes especially important after a 12.6% one-day rally. Once index funds have adjusted their portfolios, RDDT returns to being valued primarily on the same variables that mattered before the announcement: audience growth, advertising monetisation, margins and Reddit’s ability to remain an important destination as artificial intelligence changes how people find information online.

Historical experience also argues against assuming that inclusion itself creates a permanent rerating. Market research cited by Stephens has found that companies newly added to the S&P 500 have often enjoyed their strongest relative performance around the announcement and inclusion period before some of that advantage faded afterwards.

The August 18 inclusion is therefore the immediate catalyst, not the end of the investment case.

How strong is Reddit’s underlying business behind the index rally?

The underlying financial numbers are considerably stronger than the recent volatility in RDDT might imply.

Second-quarter revenue increased 61% year on year to US$805 million, marking Reddit’s eighth consecutive quarter with revenue growth above 60%. Advertising revenue rose 64% to US$762 million, while other revenue increased 24% to US$43 million.

Profitability expanded even faster.

Net income increased to US$253 million from US$89 million, producing a net margin of 31.4%. Adjusted EBITDA more than doubled to US$343 million, while the adjusted EBITDA margin expanded to 42.6% from 33.4%.

Free cash flow reached US$261 million compared with US$111 million a year earlier.

Reddit is therefore no longer being valued solely on a future promise of profitability. The company is already producing substantial earnings and cash while continuing to grow revenue rapidly.

The Q3 outlook points to further expansion. Management expects revenue of US$860 million to US$870 million and adjusted EBITDA of US$385 million to US$395 million.

At the midpoint, Q3 revenue of US$865 million would represent approximately 7.5% sequential growth from Q2. The midpoint of adjusted EBITDA guidance, US$390 million, would imply an adjusted EBITDA margin of approximately 45.1%.

That would represent another meaningful step higher from the 42.6% margin achieved during Q2.

For investors assessing RDDT after the S&P 500 announcement, this is arguably more important than the index buying itself. Reddit is attempting to demonstrate that rapid revenue growth can coexist with increasing operating leverage rather than requiring an equally rapid expansion in costs.

Why are investors still worried about Reddit’s user growth?

The main operating concern is not advertising demand. It is the pathway through which users arrive at Reddit.

Global daily active uniques increased 18% year on year to 130.3 million during Q2. International DAUq increased 28% to 77.1 million, but United States DAUq grew only 6% to 53.2 million.

The monetisation difference between those regions is substantial.

United States average revenue per user reached US$11.85 during Q2, up 51% year on year. International ARPU was only US$2.26 despite growing 31%.

That means slower United States user growth matters disproportionately because each United States user currently generates more than five times the revenue of an international user.

Management has identified volatile external search referrals as one factor affecting traffic, particularly among users who reach Reddit through the web without being logged in.

Reddit’s United States logged-in DAUq increased only 1% year on year to 23.1 million during Q2, while United States logged-out DAUq grew 10% to 30.1 million.

The company is trying to turn more visitors into repeat direct users through improvements to its app, search, personalisation and broader product experience.

That is the key user-growth test for the next several quarters.

Reddit does not necessarily need external search traffic to grow indefinitely if it can convert more visitors into regular logged-in users. But continued dependence on volatile search referrals would leave an important part of audience acquisition outside Reddit’s direct control.

Can Reddit’s monetisation growth compensate for slower US user expansion?

So far, the answer has been yes.

United States revenue increased 56% during Q2 despite United States DAUq rising only 6%. The difference was driven by significantly higher monetisation, with United States ARPU increasing from US$7.87 to US$11.85.

International revenue increased even faster, rising 84% to US$167 million as both audience size and monetisation improved.

That combination explains why total revenue can continue growing above 60% even though headline user growth is considerably slower.

The question is how long monetisation can keep carrying such a large portion of the expansion.

Reddit is improving advertising technology, measurement and targeting while attracting additional small and medium-sized advertisers alongside large brands. Its vast collection of interest-based communities gives advertisers access to conversations around products, hobbies and purchasing decisions that can be difficult to replicate on more general social platforms.

The company also benefits from an exceptionally high gross margin. Q2 gross margin reached 91.3%, providing substantial operating leverage as revenue scales.

At the same time, advertising still generated roughly 95% of Q2 revenue. Reddit is therefore primarily an advertising business despite growing interest in data licensing and other potential revenue streams.

A stronger long-term investment case would emerge if Reddit can combine higher advertising monetisation with renewed United States user growth rather than relying on ARPU expansion to offset slower audience gains.

Is Reddit expensive at US$178 after the S&P 500 rally?

At Friday’s US$178.09 close, Reddit’s market capitalisation was approximately US$34.3 billion.

Current market data places its trailing price-to-earnings ratio around 41 times.

That is a premium valuation, but it needs to be considered alongside an unusually high growth rate. Q2 revenue increased 61%, net income increased 183% and adjusted EBITDA increased 106%.

The valuation becomes harder to support if those growth rates normalise rapidly.

Reddit also has a strong balance sheet. Cash, cash equivalents and marketable securities totalled approximately US$2.79 billion at June 30.

The company repurchased 1.5 million Class A shares during Q2 for US$235 million at an average price of US$157.57.

Friday’s US$178.09 close is approximately 13% above the average price Reddit itself paid during the quarter. That does not establish whether the stock is expensive or cheap, but it illustrates how quickly the valuation has changed since management was actively repurchasing shares.

Dilution also appears relatively controlled at present. Reddit reported 207.0 million fully diluted shares outstanding at the end of Q2, up only 0.2% year on year despite continuing equity compensation.

The balance sheet and cash generation therefore provide meaningful financial support. The primary valuation risk comes from expectations rather than funding.

At around 41 times trailing earnings, Reddit needs continued rapid growth. A shift from 60%-plus revenue growth toward conventional social-media growth rates without corresponding valuation compression would be difficult to reconcile.

What could weaken the Reddit investment case after August 18?

The first risk is that the index rally proves temporary.

The S&P 500 addition creates a near-term source of demand, but that buying is finite. Once passive funds have adjusted their portfolios, further returns depend on operating performance.

The second risk is continued volatility in United States user growth. The United States remains Reddit’s most valuable advertising market by a wide margin, and only 6% DAUq growth leaves less room for traffic weakness than the 28% international increase might initially suggest.

The third risk is valuation.

Reddit is producing exceptional financial growth, but a roughly 41-times trailing earnings multiple leaves the stock sensitive to any evidence that revenue, ARPU or margins are decelerating faster than expected.

These risks are balanced by strong evidence on the other side. Revenue is still growing above 60%, free cash flow has more than doubled, EBITDA margins are expanding and the Q3 outlook implies another sequential increase in both revenue and profitability.

Reddit stock key takeaways before S&P 500 inclusion

• Reddit shares jumped 12.6% to US$178.09 on August 14 after S&P Dow Jones Indices confirmed RDDT will enter the S&P 500 before trading begins on August 18.
• J.P. Morgan estimates index-tracking funds could need to acquire about 16.7 million Reddit shares, equivalent to roughly 2.8 times the stock’s average daily volume since its IPO.
• Q2 revenue increased 61% to US$805 million, while adjusted EBITDA more than doubled to US$343 million and free cash flow reached US$261 million.
• The midpoint of Q3 guidance implies approximately US$865 million of revenue and a roughly 45.1% adjusted EBITDA margin.
• United States user growth remains the central operating concern, with U.S. DAUq rising only 6% compared with 28% international growth.
• Reddit’s approximately US$34.3 billion market value and roughly 41-times trailing earnings multiple require continued strong revenue and profit expansion after index-related buying fades.
• The next proof points are the August 18 index inclusion, sustained U.S. audience growth and delivery against the US$860 million to US$870 million Q3 revenue outlook.

What would strengthen or weaken the Reddit investment case from here?

Reddit enters the S&P 500 with operating numbers that justify its inclusion as more than a market-capitalisation milestone. Revenue has grown above 60% for eight consecutive quarters, profitability is expanding rapidly, free cash flow is substantial and management expects another increase in revenue and adjusted EBITDA during Q3.

The investment case would strengthen if United States DAUq growth begins accelerating again, Reddit continues increasing ARPU without damaging advertiser returns and Q3 adjusted EBITDA margin approaches the roughly 45% level implied by current guidance. Continued international user growth would become more valuable if the monetisation gap with the United States also narrows.

The thesis would weaken if search-driven traffic becomes increasingly volatile, United States users stagnate or advertising growth slows materially once current monetisation improvements mature. A rapid revenue slowdown would matter particularly because the stock still carries a premium earnings multiple even after remaining well below its 52-week high.

The S&P 500 addition gives RDDT a powerful near-term catalyst and potentially millions of shares of index-related demand. What happens after August 18 will matter more. Reddit now needs to demonstrate that the business attracting passive index capital can also keep attracting users, advertisers and cash flow quickly enough to justify the valuation left behind once that forced buying is complete.